From user Roland Deschain at OccultCorpus:
"Just because karma is from a different country and culture does not mean it wasn't invented to keep the Hindu masses in order. Belief in karma is just a restraint for our morals. I can decide on my own what is right and wrong, and so can you. If some of you are afraid your magickal fire is going to come back and burn you, maybe you shouldn't play with it."
This matches closely with my thoughts on karma in magic.